This paper describes an event-based, process-oriented, ephemeral gully erosion model for predicting soil erosion by concentrated overland flow from fields and small catchments. It is designed as a new component for the European Soil Erosion Model (EUROSEM). The ephemeral gully model uses a transport capacity approach to simulate simultaneous soil detachment, transport and deposition. Discharge and sediment concentration are calculated by solution of the dynamic mass balance equations for water and sediment respectively. The model accounts for changes in gully geometry due to lateral erosion, bed degradation, bank failure, and sediment deposition. The bank failure sub-model assumes cantilever failure dominates and is related to cantilever width, bank geometry, and the influence of rapid drawdown. Key features of the model are outlined together with plans for further research.